Lock nut



Dee, 29, 1931.

W. YOULTEN LOCK NUT Filed June 27. 1929 Patented Dec. v 29, 1931 A UNITED STATES PATENT OFFICE WILLIAM YOU'LTEN, OF HOVE, ENGLAND, ASSIGNOR TO EVEBTITE LOCKNITTS LIMITED,

OF LONDON, ENGLAND LOCK NUT Application fled June 27, 1929, Serial Ilo. 374,079. and-in Great Britain November 19, 1924.

This application is a continuation in part of my application, Serial No. 43,325, filed July 13th, 1) 25..

This invention relates to locknuts and has for its object to provide an improved form of 'locknut of the kind consisting of a single internally screwed unit or body of desired form having in its interior and in desired proximity to one end an annular groove which permits of distortion of the nut body taking place when the nut is drawn up against the work piece or abutment with said end of the nut engaging-the abutment. The workengaging end face of such a nut is frequently 1| so bevelled that the part thereof nearest the bolt comes first into contact with the work piece or abutment so as to localize the reaction' where it may be most effective in produc ing the distortion. I 80 It has now been found that if the groove instead of being of a square or rectangular section as already known, is of wedge or V-section, and such means are included as produce the desired localizing of the reaction, the :6 locking action brought about in the screwing up may be much improved. The conditions necessa besides the provision of a V-groove as distinct from a rectangular groove are that the groove should be so located as to leave suflicient thread surface to avoid crushing or damage to the threads, say about two threads, between it and the work-engaging end face and to provide a region of weakness in the nut body disposed sufliciently above the lower threads to ensure elastic flexure maintaining inward radial pressure on said threads.

In the case of shallow nuts the annular groove may come substantially at the middle ifications will now be described with reference to the accompanying drawings in which:-

Figures 1, 2 and 3 show in front and sectional elevation and plan respectively a locknut made according to the invention;

Figures 4 and 5 are sectional elevations like Flgure 2, showin modified forms of locknuts according to the 1nvention, these being of the same external configuration. as the nut shown in Figures 1 to 3.

Referring to Figures 1, 2 and 3, 7 is the nut having one end surface 8 bevelled as shown. 9 is-an annular V-shaped groove out into the material of the nut from the interior near the bevelled or rounded work-engaging end face 8, substantially two complete threads being left between the groove 9 and the end face 8. The upper end of the nut is flat and chamfered in the usual manner.

The internal annular groove 9 as shown has a lower conical surface 10 with an apex located below the groove and in proximity to the plane of the end face 8 so as to give a region of weakness in the nut body-disposed sufficiently above the lower threads to en sure elastic flexure brought about in the screwing up maintaining inward radial pressure on the threads located below the groove. That is, by disposing and locating the groove as shown in Figure '1, the weak region of the nut body will not only be concentrated around and local to the. bottom of the groove but will also be located very considerably above the lower few threads with the result that as the nut is screwed home fiexure of the nut portion which includes the lower threads I will take place quite sharply about points substantially level with the bottom or centre of the groove and the lower threads will'be forced substantially radially inwards against the bolt threads. Further, each of the lower threads will be forced to substantially the same extent against the bolt threadsand the pressures producing the locking action will thus be uniformly distributed over these threads resulting in substantiall no damage thereto or to the threads of the It.

The movements and distortions in pulling 1 up such nuts with the ordinary force are slight and practically within the elastic limit of the material of which the nut is made but they are none the less real, and effective locking is produced.

As will be appreciated, flexure of the nut body and movement of the lower threads are brought about by the bevel 8 localizing the reaction adjacent to the bolt and are defined by the conditions under which the V shaped annular groove 9 is provided.

In a modification of the invention the V- groove instead of being determined by two opposed and similarly inclined conical surfaces may comprise say only one coned surface, that is, the surface 10 adjacent the workengaging end surface of the nut which coned groove surface would conform with the conditions set forth as to the location of its apex and the number of threads left below the groove. The other or opposed surface 11 of the groove may be anything from a flat or substantially flat annular surface in a plane suitably remote from the work-engaging face of the nut (as shown in Figure 4) to a coned surface which may if desired (as' shown in Figure' 5) have its apex also directed towards the work-engaging face of the nut and may intersect the lower coned surface in a plane above the interpenetration of the groove and the nut threads.

Nuts made according to the invention in practice 'act as extremely efficient locknuts and do not work loose or become detached even under long sustained vibration, when attaching the nuts in (position only-the normal tightening is require v The materials from which locknuts according to this invention may be made may be, as usual, mild steel, bronze, drawn brass or others or even'for large sized nuts cast metals such ashave a sufficiently high elastic limit as to accommodate the elastic flexure requiredto produce the desired locking effect, and preferably also such that any permanent set of the nut body will not take place under the forces of screwing up the nut to the extent to which plain ungrooved nuts of similar dimensions are ordinarily screwed up.

It should also be observed that in many instances nuts made according to the invention may replace riveting with advantage.

The invention is not limited to the practical embodiments shown as it may be applied to capped nuts, that is nuts with one closed end.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1-- 1. A locknut comprising an internally threaded body with a single annular V-section groove fromed internally to provide a region of weakness therein and located to leave substantially two threads towards the work-engaging end face, said work engaging end being of convex form for localizing contact of said face with the work adjacent to said last mentioned threads, said region of weakness being localized in a single plane considerably more remote axially than said last mentioned threads from said work engaging convex end face whereby on screwing up against the work, elastic fiexure of that portion of the nut body which includes said last mentioned threads ensures positive and substantially uniformly distributed inward radial pressure of said threads upon the male threaded element.

2. A locknut according to claim 1, wherein the number of threads above the V shaped groove are greater than the number between said groove and the working face of the nut.

3. A locknut according to claim 1 with the side of the groove adjacent said work engaging end face conforming to the surface of an imaginery cone whose apex if the cone were complete would be in proximity to a plane tangent to said work engaging end face.

4. A locknut according to claim 1 wherein the sides of the groove conform respectively to the surfaces of two imaginary cones, that to which the groove side adjacent said threads conforms terminating in an apex disposed in proximity to a plane tangent to said end face.

5. A locknut according to claim 1 wherein the sides of the groove conform respectively to the surfaces of two imaginary cones, that to which the grooved side adjacent said threads conforms having an apex disposed to the same side of said plane as are said threads and the apex of the other cone being directed also towards said end face.

In testimony whereof I have signed my name to this specification.

WILLIAM YOULTEN. 

